AT&T is bringing their AIO Wireless prepaid brand nationwide starting mid-September. AIO offers two plans that can be used for Smartphones; Aio Smart and Aio Pro. Both plans offer unlimited talk, text, and data, with data being throttled after a pre-set allotment (so no overages, unlike AT&T's other offerings). Here is the pricing on these two plans as well as how they compare to AT&T's GoPhone and contact offerings, as well as T-Mobile's plans. Please note that GoPhone and AIO are per line, so while they are extremely cheap for a single-line, they can't compete on 3+ line family plans.

AT&T GoPhone - offers unlimited talk/text and 2GB of data for $60/mo, overages of $10/GB, no other plan

AT&T Contract Plans - $69.99/mo for unlimited talk, $30/mo for unlimited text, and $30/mo for 3GB of data with $15/GB overage charge. So the base plan is 3GB of data for $129.99/mo, or $149.99/mo if you want the 5GB data option.

AT&T Mobile Share (Contract) - $95/mo nets you unlimited talk and text plus 2GB of data with $15/GB overages. This can be upped to 6GB for $125/mo.

Ranking: (accounts for average subsidy difference of $450 over 24 months between prepaid and contract plans)

AIO 2GB - $55 ($73.75)

T-Mobile 2.5GB - $60 ($78.75)

AT&T GoPhone 2GB - $60 ($78.75)

T-Mobile Unlimited - $70 ($88.75)

AIO 7GB - $70 ($88.75)

AT&T Mobile Share 2GB - $95

AT&T Mobile Share 6GB - $125

AT&T Classic 3GB - $129.99

AT&T Classic 5GB - $149.99

Keep in mind that this is amongst plans with unlimited talk and text. For those who use little to no talk time, T-Mobile's $30/mo plan still wins. So, that aside, there are two takeaways from this.

First, AIO is a very competitive offering leaving no purpose for GoPhone. The AIO offering is $5 cheaper for the same allotment and offers throttling as opposed to overages. And if you prefer more high-speed data, the 7GB plan is offered at the same price as the 2GB GoPhone plan with a 1GB overage. T-Mobile is still competitive here for offering a truly unlimited option at the same price as AIO's 7GB plan. However, I suspect that most will have better AT&T coverage as opposed to T-Mobile.

The second takeaway is that ALL of the prepaid plans do better than ALL of the contract plans, even when you account for the industry average of $450 on the subsidy and assuming a 2-year upgrade cycle. For a single-line plan, there is no reason to go with AT&T's contract plans anymore.

However, family plans will be better served using either T-Mobile, or going with AT&T's Mobile Share. Adding a second line to T-Mobile's plan starts at $30 (and then $10 for each additional plan). For Mobile share, it's $35-$50 per line, depending on your data allotment. For AIO and GoPhone, they are separate plans with the same cost per individual.